Projectile fuse



June 19, 1945. FANGER I 2,378,626

' PROJECTILE FUSE Filed April 6, 1942 F1" E J.

16 I -43 INVENTOR. 2 HERMAN J FAA/GER Patented June 19, 1945 PROJECTILE FUSE Herman J. Fanger, Piedmont, Calif., assignor of thirty per cent to Martin C. Mogensen, Martincz, thirty per cent to Herbert W. Erskine, Piedmont, thirty per cent to Cleve F. Shafier, San Francisco, and live per cent to Henry Gruenhagen, Oakland, Calif.

Application April 6 1942, Serial No. 437,734

6 Claims.

This invention relates to explosive projectiles as used in warfare, and particularly to such as are fired from guns or mortars, and the principal object of the invention is to provide an improved automatic detonatin head or fuse construction embracing features of sensitiveness and adjustability for operation at solid or partial impact or retardation as from very slight impact such as when the projectile enters light shrubbery.

Other features and advantages of the invention will appear in the following description and accompanying drawing.

In the drawing,

Fig. l is a longitudinal sectional view of the forward portion of a projectile showing my improved fuse mechanism in place and with the outer shell of the mechanism shown in section.

Fig. 2 is a similar longitudinal view to that of Fig. 1 but taken at right angles thereto, and with the fuse mechanism shown in section.

Fig. 3 is a view like that of Fig. 2 but with the fuse mechanism shown in the act of detonating the cup.

Fig. 4 is an enlarged sectional detail of Fig. 1 showing the means for adjusting the latch collar retaining magnet.

Fig. 5 is a sectional detail similar to that of Fig. 4 but showing a frictional retaining device for the latch collar instead of a magnet.

Fig. 6 is a cross section of Fig. 3 as seen from the line 6-6 thereof.

Fig. 7 is a cross section of Fig. 3 taken along the line 1-1.

Before describing the drawing in detail .it may be stated that the mechanical fuse comprises a spring actuated firing pin normally held or locked in retracted position from an explosive firing cup by means of a ball latch device in which a plurality of bearing balls are engaged between a shoulder formed on the firing pin and an inertia displaceable collar which is moved in one direction at the moment of firing the projectile from a gun, due to inertia of the collar, held temporarily in this position by an adjustable magnetic or frictional clutch, and released and moved in the opposite direction upon impact of the projectile (or even any sudden slowing down of its speed of travel from any cause) so as to release the balls from locking position and thereby release the firing pin for operation by the energy ofits reloaded with any desired type of explosive (not shown). 2 is the rounded or conical nose piece of the projectile held in place by a hollow cup-like member 3 forming a casing for the fuse mechanism and formed with a bottom wall 4 anda return or reentrant tubular fiange 5 providing a bore 6 for the enlarged shank l of a firing pin 8 which is slidably disposed in the bore in alignmentwith an explosive cap 9 for firing the charge of the shell or projectile (not shown) Fuse casing 3 is seated in a suitable counterbore in the end of the projectile and secured firmly therein as by threading as at It! and/or set screws H, or other suitable means and at its outer open end the casing 3 embraces the margin of th base of the nose piece 2 which is reduced in diameter to receive it and further formed with a groove 12 1 which extends around the base of the nose piece.

The fit of the casing 3 in its embracing relation to the base of the nose piece is free so that the nose piece may be manually revolved within the casing, but to prevent bodily withdrawal and also to limit the degree of turning of the nose piece within the fuse casing several lugs or pins extend from the casing into the annular groove I2. These lugs are conveniently formed by inwardly indenting the casing as at l3, while to limit the degree of revolvability of the nose piece one or more fixed pins I4 project from the bottom of the groove, and to facilitate turning the nose piece it may be provided with a knurled band I5 and/or spanner wrench depressions it.

The base of the nose piece is provided with an extending hub ll centrally bored as at 18 in confrontin relation to a similar bore I9 formed in the enlarged shank l of the firing pin, and in which confronting bores is freely positioned a coiled spring 20 always under compression tending to force the firing pin into the cap 9.

Tubular flange 5 of the fuse casing extends or returns within casing 3 somewhat more than half its depth and is bored out larger for about two thirds its length as at 28 to form a thinner section 22 and to provide a substantial space between it and shank l and provided with two or more holes 23 in its wall which freely each receive a ball 26, such as a steel or bronze bearings ball, and the extreme outer end of the firing pin shank l is outwardly flanged as at l to engage the inner sides of the balls in a manner tending to force the balls outward through the holes 23 as the spring 20 urges the firing pin shank toward the cap, and if the balls were not restrained from such outward movement they would fly out and the firing pin would be operated.

However, in order to hold the balls from flying out until it is desired to fire the cap, a collar 25 slidably surrounds the flange 22 and overlaps the balls as shown in Fig. 2 and is normally held in this position by a pair of hooks 26 which are carried by the nose piece 2 to which their shanks 21 are rigidly secured. These hooks are flat in form and each extends in overlapping but free relation to collar 25 within a relatively widecutout portion or slot 28 formed in the outer sides of the collar, and which cut-out or slot is provided with a notch 29 into which the hook engages, as best shown in Fig. 1, when the nose piece 2 is turned to the left as far as it will go. But when the nose piece is turned to the right the distance permitted by stop pin M the hook will be free of the notch, and also the shank 21 will not quite touch the opposite edge of the cut-out or slot 28 so that collar 25 will be free to slide longitudinally back and forth. The collar is of such a length that when slid outward or forwardly of the projectile it will uncover the balls and permit them to be forced outward by the action of spring and the firing pin to be operated, but if the collar is slid inwardly its length is such that it will not uncover the balls.

When the collar slides inwardly or toward the body of the projectile it meets a ring type permanent magnet 30 or plurality of magnet sections carried by or forming the ring, and as the collar is of steel or other magnetic material it will be retained by the magnet. The ring magnet surrounds the internal flange or hub 5 and is adjustably held in place as by screws 3| so that by turning the screws the ring will be more or less advanced or retracted and the screws more or less project through it so as to form a stop for the collar 25 before it touches the magnet (see Fig.4). or permit solid contact, all depending on the holding effort desired on the collar for the particular service of the projectile.

Instead of holding the collar 25 at its inner sliding posit on by a magnet, it may be done frictionally by the modified construction shown in Fig. 5 wherein the collar 25 is formed with a retaining groove as at 32 and beveled off as at 33 to receive one or more fiat spring detents 34 which may be clamped in place under a ring 35 taking the position of the magnetic ring previously described and the spring detents may each be provided with adjusting screws 36 for varying their effective frictional contact with the groove 32.

The usual safety or so called priming pin is provided. such as a manually removable cotter pin 31 which extends through coinciding holes in the nose piece 2 and casing 3. Also one or more soft metal wire shear pins 38 project through the casing into the slidable collar 25 to hold it in central osition.

To prevent the collar 25 from turning as the hooks 26 are engaged or disengaged by manually turning the nose piece the collar is longitudinally splined at; one or more places and operates freely along feather keys 39 suitably secured to the cas ng 3.

In operation. after removal of the priming pin 31. the nose piece is turned to the right as far as it will go. to thus release the hooks 26 from the collar notches, and the projectile is inserted in the gun and fired. Due to the inertia of the relatively thick iron or steel collar 25 it slides to the left, breaks the shear pins 38, and is held by the magnet 30 (or spring clutch 34) at the inner position, until the projectile strikes its ob- .iective, or comes to a sudden change in speed and whereupon the collar 25 being heavy will at once break away from its magnetic or clutch retention and slide forwardly to uncover the firing pin locking balls to release them to fall to the bottom as shown in Fig. 6. The firing pin of course instantly coming into action.

By reason of the adjustability of the magnetic or frictional retention of the collar 25 in the inner position it is possible to have the adjustment so that the retentive effect is very slight and that in consequence the projectile will be exploded at least slowing up in the speed of its forward mo tion from any cause, such as the penetration of the fabric of an airplane wing, or even light shrubbery, Or even from the downward turnin of the projectile from the highest point of its trajectory.

Having thus described my improvements in a mechanical fuse for projectiles what I claim is:

1. In a projectile fuse mechanism including a casing, a slidably mounted firing pin member within the casing, a longitudinally movable inertia collar spaced outwardly from and surrounding said pin member, a latching element positioned between the slidable collar and said pin member and engaging the latter against firing movement, said collar formed to release said latching element upon relative forward sliding of the collar through its momentum set up upon and by impact of the fired projectile, and means within the fuse casing for controlling the effective response of said inertia collar to such forward impetus, and manuall operated means accessible exteriorly of said projectile adapted for locking and unlocking said collar against movement.

2. In a projectile fuse mechanism including a casing, a slidably mounted firing pin member within the casing, a longitudinally movable inertia collar spaced outwardly from and surrounding said pin member, a latching element positioned between the slidable collar and said pin member and engaging the latter against firing movement, said collar formed to release said latching element upon relative forward sliding of the collar through its momentum set up upon and by impact of the fired projectile, and means within the fuse casing for controlling the effective response of said inertia collar to such forward impetus, and manually operated mean accessible exteriorly of said projectile adapted for locking and unlocking said collar against movement comprising a nose piece on said projectile, means mounting said nose piece for rotary motion with respect to the projectile, a hook carried by the nose piece extending adjacent said collar and arranged to engage and disengage with the collar as the nose piece is turned one way or the other.

3. In a projectile fuse mechanism including'a casing, a slidably mounted firing pin member within the casing, a longitudinally movable inertia collar spaced outwardly from and surrounding said pin member, a latching element positioned between the slidable collar and said pin member and enga ing the latter against firin movement, said collar formed to release said latching element upon relative forward sliding of the collar through its momentum set up upon and by impact of the fired projectile, and means Within the fuse casing for controlling the effective response of said inertia collar to such forward impetus, and manually operated means aci above within the casing.

- or the other.

' between said collar and said en aging the latter against tiring movement. a

cessible exteriorly oi said projectile adapted for locking and unlocking said collar against movement comprisin a casing enclosing the parts described and countersunk in the iorward end of the projectile, a nose piece on said promeans mounting said nose piece for rotary motion with respect to said casing, a hook carried by the nose piece extending adjacent said collar and arranged to engage and disenga e with the collar as the nose piece is turned one way or the other.

4. In a projectile fuse mechanism including a casing. a slidably mounted iiring pin member a longitudinally movable inertia collar spaced outwardly from and surrounding said pin member, a latching element positioned between the slidable collar and said pin member and en aging the latter against tirin movement, said collar formed to release said latching element upon relative forward sliding of the collar throughits momentum set up upon and by impact 'of the tired projectile, and means within the fuse casing i'or controlling the eiiective response of said inertia collar .to such forward-impetus, and manually operated means accessible exteriorly 0! said projectile adapted for locking and unlocking said collar against moveabove described and countersunk in the iorward end of the projectile, a nose piece on said projectile, means mounting said nose piece for roholdin the ball tary motion with respect to said casing, a hook carried by the nose piece extending adjacent said collar and arranged to engage and disengage with the collar as the nose piece is turned one way and a manuall removable priming pin passing through said nose piece and said casing for locking them together.

5. In a projectile iuse mechanism. a slidably mounted firing pin member. a longitudinally movable inertia collar spaced outwardl from and surrounding said pin member, a hall positioned firing pinmember ball retainer between the collar and said member against longitudinal movement but permitting outward movement oi said ball and thereby the release oi said member, said collar being of a length to release said ball onlynpon forward movement or the collar while tree .ior limited rearward movement due to its inertia upon tiring the projectile without releasing said ball, and clutching means adapted to temporarily retain said collar in rearward .position after flring. and to release said collar for forward movement due to its momentum upon impact of the projectile, said collar including magnetic ma- 1 terial, and said clutching means comprising a ermanent magnet at the rearward end oi movement of the collar arranged to magnetically hold the collar in temporary rearward position asdescribed.

8. In a projectile fuse mechanism, a slidably mounted tiring pin member, a longitudinally movable inertia collar spaced outwardly from and surrounding said pin member, a ball positioned between said collar and said tiring pin member engaging the latter against tiring movement, a ball retainer between her holding the ball againstlongitudinal movement but permitting outward movement of said ball and thereby the release of said member, said collar being of a length to release said ball only upon forward movement of the collar while free ior limited rearward movement due to its inertia upon firing the projectile without releasing said ball, and clutching means adapted to temporarily retain said collar in rearward position alter iiring, and to release said collar for forward movement due to its projectile. said collar including magnetic material, and said clutching means comprising a permanent magnet at the rearward end oi movement oi the collar arranged to magnetically hold the collar in temporary rearward position as described, and means for adjusting the effectiveness oi the magnet inv holding said collar.

WAN

J. venom.

the collar and said memmomentum upon impact of the 

